One application of the occlusion resistant catheters disclosed herein is in shunting systems for cerebral-spinal fluid for use in treating hydrocephalus. Conventional shunting systems used for this purpose typically include three components: a ventricular catheter portion; a peritoneal catheter portion; and a valve located between the two catheter portions. The catheter portions typically are formed from a flexible synthetic polymer such as silicone rubber. A proximal end of the ventricular catheter portion is configured for insertion in a cerebral ventricle. A distal end of the peritoneal catheter portion is configured for insertion in a body cavity, or in some cases configured to drain fluid outside of the body. In many cases it would be preferable that all three components be implanted subcutaneously and left in place for many years.
The purpose of the shunting systems when treating hydrocephalus is to affect periodic drainage of excess cerebral-spinal fluid from the cerebral ventricle. The cerebral ventricle that is typically drained is ventricle III. The cerebral-spinal fluid is drained from the cerebral ventricle in order to maintain proper endro-cranial tension or pressure at normal physiological values.
Conventional shunting systems for treating hydrocephalus suffer from occlusion of the fluid path through the shunt, typically at the inlet in the proximal end of the ventricular catheter portion and/or at the outlet in the distal end of the peritoneal catheter portion. Many attempts have been made to design clog resistant tips and orifices, however most have not met with much success. Blockage in the fluid path typically occurs as a result of tissue ingrowth and/or protein buildup in and around these orifices, often the result of the deposition of filaments of fibrin. Such blockage will often render the shunting systems useless in less than two years after implantation, requiring frequent replacement of the shunt. Such replacement procedures can be expensive, uncomfortable for the patient, and expose the patient to unnecessary complications associated with the procedures.
Further information relating to the treatment of hydrocephalus with conventional shunting systems may be found in U.S. Pat. No. 4,375,816 to Labianca and U.S. Pat. No. 7,582,068 to Koullick et al.
What is needed and is not provided by the prior art are implantable shunting systems that can be used in the treatment of hydrocephalus, and in other medical applications such as hemodialysis, without occlusion and tissue ingrowth.